Grinding machine



Sept. 18, 1928. 1,684,486

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W. J. GUILD ET AL GRINDING MACHINE Original Filed Jan. 7, 1926 8Sheets-Shee 4 .Sept. 18, 1928.

W. J. GUILD ET AL GRINDING MACHINE Original Filed 7, 1926 8 Sheets-Sheet5 wM w% RQ QQN .Zr'zwrzzra: 7 Web I 6201a? [eh 1%? A4922 arz (m /WMSept. 18, 1928.

W. J. GUILD ET AL GRINDING MACHINE Original Filed 7, 1926 8 Sheets-Sheet6 n In I gal lFzwnfars; Wilda 7. 'azld Laws 6. Kenya/z Sept. 18, 1928.1,684,486

w. J. GUILD ET AL GRINDING MACHINE Original Fi'ledJanfl, 1926 8Sheets-Sheet v lei/5 c1 Ian 072 Sept. 18, 1928.

w. J. GUILD ET AL GRINDING MACHINE Original Filed 7, 1926 8 Sheets-Sheeta I Jrzaavzf'orsx W0 0 .Z' fiat/d Zeb 11s 63 Zen 0?? Patented Sept. 18,1928.

UNITED STATES PATENT OFFICE.

WALDO-T. GUILD, OF WORCESTER, MASSACHUSETTS, AND LEWIS CLIFFORD KENYON,

OF NEW YORK, Y1, ASSIGNORS TO THE HEALD MACHINE COMPANY, OF WORCES- TER,MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

GRINDING MACHINE.

Application filed Ianuary'7, 1926, SerialNo. 79,8 49. Renewed April 8,1928. i

The invention relates to grinding machines,

ment upon and an addition to the prlor in-' vention shown and claimed inthe copending application of Kempton and Gallimore, Serial No. 6,689,filed February 4, 1925, and also to the prior invention shown andclaimed in the copending application of Heald, Guild, Burns and Garno,Serial No. 4,466, filed January 24, 1925. In particular, the inventionprovides means for automatically dressing the rapidly r0- tatinggrinding wheel a plurality of times during the grinding of a workpiece,said dressing being initiated by devices responsive to the movement of agauging or calipering device that is maintained in operative relation tothe surface being ground. Between the said dressing operations thegrindi-ng wheel is brought into'contact with the work, to make at theleast a. single cutting traverse on the surface thereof. .By thusinterrupting the grinding operation two or more times to dress and truethe grinding wheel, the latter is kept sharp and free cutting, inconsequence of which the relative advance or cross feed between thewheel and the workpiece occurs without producing any spring in thegrinding wheel spindle, once the first dressing operation has occurred.

Other and further objects of the invention will appear from thefollowing detailed description, taken in connection with theaccompanying drawings, in which- Fig. 1 is a front elevation of agrinding machine built in accordance with the invention, showing thecarriage in the work removing position.

Fig. 2 is a plan view of the work calipering mechanism.

Fig. 3 is a front elevation showing the switch operating mechanism on anenlarged scale.

' Fig. 4 is a section on the line 44 of Fig.3.

Fig. 5 is a sectional view on theline 55 of Fig. 4, showing the switch,together with a wiring diagram of the machine.

Figs. 6, 7 8 and 9 are views on a reduced rear of the machine, showingthe dresser movscale of the switch mechanism of Fig. 3, showing theparts indifferent positions.

Fig. 10 is a plan view of the machine, il owilng the carriage fullywithdrawn, as in Fig. 11' is a front elevation, showing the parts in'thenormal grinding position.

Fig. 12 is a fragmentary-view from the ing mechanism.

Fig. 13 is a sectional view on the line 13-13 of Fig. 12.

Like reference characters refer to like parts throughout the drawings.

Referring first to Fig.1, the machine provides the usual reciprocatorytable or-carriage 1 which is ordinarily provided in any internalgrinding machine. In such a machine, either the grinding wheel or thework to be ground may be carried on the table 1, the reciprocation ofthe latter being utilized in either case to produce a relativetraversing movement between the grinding wheel andthe'work. As hereshown, the table 1 supports and carriesa wheel head 2, while the workwhichis to be operated upon is held in a work head 3, the latter beingcarried bya bridge 4, which spans the slideways provided by the machineframe for the back and forth movement of the table 1.-

This back and forth movement of the table 1 to cause therotatinggrinding wheel-5 to make the required interior traverse of the rotatingworkpiece 6 may be imparted in any well known manner, as for instance,by the use of the fluid pressure controlling and reversing mechanismwhich forms the subject matter of'the copending application of Heald andGuild,Serial No. 629,882, filed April 4, 1923, now Patent No. 1,582,468,granted April 27, 1926. Suchmechanism, or its equivalent, forms no partof the present invention, and a detailed descriptionthereof is thereforeunnecessary; it is sufiicient to note for the urposes of the presentapplication, that the (Friving means employed for the reciprocation ofthe table -1, be it hydraulic drive, or gear drive, or any other type,procures the reversal of said table at each end of the latters normalworking stroke by the use of spaced ad- 100 justable dogs 7 and 8,carried by theitable 1 and adapted to alternately engage and move areversing member 9; the latter, during'the at high speed in any suitablemanner, as for instance, by a belt drive for the wheel spindle 10, thelatter for this purpose carrying a pulley 10. The workpiece'6 is alsorotated, but

at a slower speed, this rotation being imparted in anysuitable manner asby a belt drive, not shown, from acountershaft.

Referring to Figs. 1, and 10, the machine also embodi'esthe usualinstrumentalities for both manual and automatic cross feed between workand wheel, here shown as embodied in a screw shaft 11 for feeding thewheel head 2 transversely of the table-,1. Said screw shaft 11 may beoperated, if desired, by. the usual hand wheel 11*. The automaticoperation of said screw shaft 11 is effected in the usual manner, ateach reciprocation of the table 1, by a fixed dog or stop.

12 which is engaged by a roller 13 on a pivoted arm 14; the movements ofsaid arm are transmitted through a pawl 14 and ratchet wheel 14 andreduction gearing, not shown, to the screw shaft 11, thereby to obtainthe automatic cross feed of the grinding .wheel 5 at each reciprocationof the table.

As shown in Fig. 2, a-member 15 has at one end a work calipering point16 adapted, during the operation of 'grinding a workpiece, to bearagainst the internal surface which is being ground, and to maintain itscontact with said surface. as the hole in the workpiece is graduallyenlarged by the grinding action of the wheel; The member 15 is to allintents and purposes a lever said member, for the movement requiredo itto maintain the point 16, in constant contact with the interior of thegradually enlarging hole in the wor iece, being ported by a pair offlexi le' U-shapedflat springs 17 and 18, which springs cross eachother, and are attached to two adjacent sides of a rectangular blockortion 19 of member 15. At their other en s the crossed springs 17 and18 are attached to two inner surfaces 20 and {21 of the box 22, thesesurfaces 20 and 21 being at right angles to each other, and the box 22providing an opening 23 of sufiicient size to permit the inwardextension 15', of member 15, to move fieel about the pivotal axis whichis afforded by the intersection of the planes of the U-shaped springs 17and 18. This pivotal movement is accom; -plished by the flexing of thesetwo springs,

and .takes place in the entire absence of lost end adapted to moveacross the grad'uations of a suitable scale 26. Lost motion may beeliminated at bearing 25 by a. spring 25. The connection betweenextension 15 and indicator lever 24 is made by a spring 27,- which drawsthe parts together and maintains the lever 24 in contact withthe end ofa screw 28, said screw being adjustably threaded in extension 15 andpassing at its head end through a suitably enlarged slot or hole 29 inboxt22, so as to permit adjustment from the exterior of said box. Fig.2, re resenting an illustrative embodiment of this mechanism, shows theend of screw 28in a cutout portion made in lever 24, but it must beunderstood that said screw and lever are entirely unconnected,

and merely bear against each other by reason of the pressure of sprin27. By turning the screw 28, the indicator lever 24 can be made toassume any desired position relative to the member 15, and said screw 28is maintained in any given setting, and displacement thereof preventedby any suitable friction device, such as a s ring 30. With thearrangement above escribed, a very slight movement of the caliperingpoint 16 is multi manipulated, being transmitted through the abovedescribed connections to the indicator lever 24.

The multiplied movement of the latter is made use of at predeterminedpoints in the grinding of each-workpiece to set in operation the wheeldressing instrumentalities a plurality of times, and finally toibringabout a cessation of the grinding and. cause the grinding wheel 5 towithdraw from the workpiece 6. To this end the lever 24 carries three ormore contacts, ,this embodiment shown as three,'namel a; -contact 32 tobring about the first stage ressing, a contact 33 to cause the dressinginstrumentalities to again come into operation, which we call the secondstage dressing, anda contact 34 to brin about the cessation ofvgrinding. In the pat s of these three contacts 32 33 and 34, the box 22provides suitable insulated stationary terminal contacts 35, 36 and 37,respectively. In the movement of lever 24, the points 32 and come firstinto con then points 33 and 36, and finally points 34 and 37, and inorder to permit this succession of contacts, points 32and33arecarriedattheendofflatsprings38 and 39 respectively, bothattached to the lever 24, so that by the yielding of these springs, thesubsequent movement of said lever to' bring the point 34 into contactwith point 3? can take place with a negligible resistance.

As clearly described in the application of Heald, Guild, Burns andGarno, the box 22 is mounted for swinging movement about .a pivot 40,and when the final withdrawal movement of table 1 takes place,withdrawing the wheel 5 from the workpiece" 6, a cam member 41 strikes aroller 41' on an arm 41 attached to the box 22 andswings the box 22,carrying the calipering lever 15, away from the workpiece. A spring 42,see Fig. 1, automatically returns the box 22 to its operative positionas the wheel 5 enters a subsequent workpiece 6, and means is provided toallow the calipering point 16, generally a diamond, to enter the newworkpiece without striking the mouth of the latter and chipping thepoint 16. It is not believed'necessary to describe these mechanisms andthe various adjustments in detail, as they have nothing to do with thepresent invention, and enough of the calipering mechanism has beendescribed to illustrate said present invention. i

Referring now to Fig. 5, the instrumentali ties of the presentinvention, whereby a plurality of wheel dressing operations may beautomatically inaugurated; will'now be described. The character Gindicates a generator of any desired sort, preferably suppl ing directcurrent. One terminal of the said I generator is grounded and the otherterminal is connected by means of a branching lead 43 to the coils oftwo elcctroma ets 44 and 45. The other end of the coil 0 eIect-romag-Fnet 44is connected by a lead 46 toastat-iom my contact plate 47 of'aswitch, generally,

designated by the numeral 48. The other end of: the coil ofelectromagnet isco'nnected by a lead 49 to the stationary terminal 37.The stationary terminals 35 and 36 are connected respectively by leads50 and'51 to stationary plates 52 and 53, also part of said The magnet44 controls, by mechani'sm to be described, the dressing operation andwhenever it is energized, the wheel 5 is dressed by causing it to passby a diamond 54, see

' Fig. 1. The magnet 45, when energized,

brings-about a cessation of the grinding, and prepares the machine forthe intrnductlon of a new workpiece. v

Referring particularly to Figs. 3, 4 and 5, the switch 48 provides amovable bridge con tact member 55, the position of which, as hereinafterpointed out in connection with said figures and also Figs. 6, 7 8, and9, determines which of several electric circuits will be energized. Saidbridge contact member 55 is carried by an insulating collar 56. Thelatter is fastened to a melnber 57 which in turn is fastened to acentral shaft 58 of the switch. Shaft 58 supports the movable parts, ofthe switch, and is itself journalled in a sleeve casting 59 of theswitch housing. The member 57 provides a ratchet segment 57*, by meansof which the bridge contact 55 is moved into difierent positions. Theshaft 58 likewise serves as a pivot for a lever 60, the latter carryinga spring pressed pawl 61. Attached to the lever 60 is a connector 62,and when this connector is raised? the pawl 61 actuates the ratchetsegment 57 and thus turns the shaft 58 and associated parts. A hold pawl63, engaging the'ratchet segment 57", normally prevents' retrogrademovement of the shaft 58, said pawl 63 being carried by a lever 64pivoted at 65. A connector 66 is attached to the other end of this lever64, and when it is moved downwardly, the pawl 63 is raised, whereupon acoil ring 67, which has been wound up by movement of the shaft 58, actsto return the parts to original position, as shown in Fig. 3. As theouter peripheral radius of'the member 5'1 is greater than the radialdistance of the.

segment 57, the parts will be stopped as shown in Fig. 9,notwithstanding pawl 63 is raised. A spring 68 tends to hold the pawl 63in engagement with the ratchet segment 57. Before proceeding with adescription of the operation of these parts, the machinc motionsinaugurated by energizationof the magnets 44 and 45, willbe described.

Energization of the electromagnet 44 causes attraction of an armaturemember 69,- and the consequent elevation of its attachedlever'armr70,-these parts being pivoted at 71 on the frontof themachine. See Fig. 1. Such movement of the lever arm 70, responsive tothe engagement .'of contacts 32 and 35, or 33 and 36, is made use of toautomatically interrupt the grinding operation on' the workpiece 6 forthe dressing and truing of v the grinding wheel 5. This involves thewithdrawal of the grinding wheel 5 from the workpiece, and the-disposal,in the temporarily amplified path of movement of .said wheel, of thedressing -device or diamond 54; these two operations areefie'ctedthrough the mediumof the lever arm 70 in the following manner. 1 Asfully described in the copending application of Heald and Guild, SerialN 0. 25,900, filed April 25, 1925, the dressing device 54 ay be movedinto operative position through made available for the movement ofdressin I device 5 1 into'ope'rative position forms o itself, no part ofthe present invention, being fully described and claimed in theaforesaid 75 rising from the stationary frame of the grinding ivheel 5.

machine. When the lever arm 7 O is moved, a downward extension 76thereof communicates said movement to a valve 77, Fig. 1, thus ,makingthe pressure fluid active,

through piping 110 (see Figs. Hand 13),

againsta piston 111, which is operatively. associated with the member'73, thereby to swing the dresser point 54; from the inopcr'w tireposition tha t it normally occupies, down into its operative position inthe path of Referringto Figs. 12 and.13, a cylinder 112 is provided atthe rear of the machine, the piston 111 being located therein The piping110 leads from the valve'.77 tome front end of said cylinder. Alever-113, pivoted at 114, has a pin 113 which normally just touches therear end ofthe piston 111. \Vhen the latter, by fluid pressureactuation,

is moved, the lever 113 is rocked clockwise to the dotted line positionof Fig. 13-this action draws bac'kward'ly a link rod 115 to which thelever 113 is connected. The link rod is pivotally connected to thecarrying member 73, andhence the action described lowers the diamond 54.A handle 78 is also provided for'rocking the dresser manually. Ourinvcntio 1, of course, is not limited to the above described use ofpressure fluid for disposing the dresser 54 in operative position;obviously, any other type of dresser moving mechanism, such as thatdisclosed in i the said copending application of Heald, Guild, Burns andGarno, Serial No. 4,466, filed January 24, 1925, may be made responsiveto theenergization of. magnet 44.

As before stated, the other operation inaugurated by said engagement isthe autoinatic amplification of the reciproca-tory path of table 1, to.carry the wheel 5 past the dresser 54. As shown. in Fig. 1, the lefthand.

table dog 8, which limits the right hand movement of table 1, is carried.bya block 79, which instead of being secured directly to the table 1 asin the case with the block of dog 7 is mounted so as to be capableofsliding freely. longitudinally of said table. Under normal conditions,when the table is making its usual workingreciprocations to traverse thegrinding wheel 5 back and forth within theworkpiece, the block 79of dog8 is held'in definite spaced relation to a block 81, which latter, thesame as the block80 of right hand dog 7, is a stationary block adaptedto maintain its predetermined setting or adjustment longitudinally ofthe table 1, asggiven it by any suitable adjustmentof adjusting andholding devices, such for instance, as the hand screw nuts 82,82 appliedto both blocks 80 .and 81 and engaging with the screw rack 83 on thetable 1. a I d -'The device employed to hold the slidable block 79 inspaced relation to the fixed block 81 is here shown as a latch lever 84pivoted at 85 on block 81, and. having its free end disposedbygravit-yin abutting relation to a shoulder 86 on block79, therebyholding the block 79 at a predetermined distance to the right of block81. When the latch member 84 is lifted to free its end from the shoulder86, the normal connection between the slidable block 79 and the fixedblock 81 is i broken, and when this occurs on the right hand movemento'ftable 1, the dog 8 will bear without effect against the, member 9.Thus the right hand movement of the table 1 on this particularstrokewill be extended beyond the usual reciprocatory working path, andthe grinding wheel 5 will be carried out of the hole in the workpiece toa point just beyond that occupied by the dress, ing device, whichlatter, as already described,

has been moved into operative position as the amplified right handtravel of table 1 begins.

This amplified right hand travel of table 1 involves relative slidingmovement between said table and the block 79, owing tothe obstructionwhich the reversing member 9 imoses against the dog 8 to prevent theblock H 9 from moving with the table; finally, the

block 79 brings up'against the block '81,

whereupon the solid backing thus afforded for the block 79 enables. thedog 8 to shift the member 9. v This procures reversal of the table 1,and theleftj, hand movement of said table .thusinauguratedis caused torestore the parts automatically to normal position in,

the following manner. v p

i A member 87 pivotally mounted on the frame of the machine has a pairof inclined surfaces 88 and 89 for cooperation, respectively, withinclined surfaces 90 and 91 at the lower corners of the block 79'. Aspring 92 presses said member 87 upwardly. In the normal grindingoperation ofthe machine when the blocks 79 and 81 are connected by latch84:, the surfaces 88 and 89, although in the path of block 79, offer noeffective ob'- struction ,to the back andforth travel of said block-inunison with the table 1,.it being obvious that when either lower cornerof the block under these conditions strikes either of the bevelledsurfaces 90 or 91, such contact will wedge the spring 92 downwardly.saidspring yielding sufliciently to allow the block 79 to pass over themember 87. However,

when the block-J9 has been freed from the block 81 as above described,to, amplify a. single right hand stroke of the table 1, the ensuingreversal of said table, with the block.

- 2'9 still free, tindsthe surface 88 in position to contact with thecorner 90 of' said block, and under these conditions; the obstructionoffercd sufficient to overcome whatever friction there may be tending tocause the block 7 9 to move totheleft with the table -.The block 79;being thus held stationary while the table 1 and block 81 continuetomove to the left, the latch member 84 finally resumes its normalposition relative: to the block 7 9 the end of said latch memberdropping behind the shoulder 86 .and the parts being thus automaticallyrestored to normal position at the conclusion of each single amplifiedreciprocation of the t ble 1. Movement of the lever arm 70 is ad-pted tothe latch 84, the former having a roller 70, which normally lies justunderneath. said latch.

The magnet may be seen in dotted lines in Fig. 1, being shown as.inclosed in a box like structure 93 on the front of the machine frame.The magnet is: located directly behind the magnet 4.4, andthe same pivot71 that serves to hold the armature 69, lever arm and extension 76-,serves also to hold an armature 94: and arm 95 associated with elec-,tromagnet 45. As heretofore stated, energization of ma I ct 45 isadapted to cause final separation ol work and wheel, and this iseffected in the following manner z-' Attraction of armature 94 lifts arm95, in terposing the free end of the latter in the path of table dog 8,which dog, as heretofore pointed out, normally on the right hand workingstroke of the table, strikes and moves the reversing member 9 to causes.reversal in the direction of table travel. The dog 8 pivotally mountedat'96 (see Fig. 1) on'the carrying block 79 and normally rests bygravity against a pin 96. When the arm 95, as above described. movesupwardl into the pathof do 8, the free end of said og onthe right hanmovement of the table, engages with and rides upon the u wardly inclinedsurface of arm 95, and is t us carried clear of reversing member 9. Thetable 1 therefore, continues its movement to the ri ht, ca'rrying thegrinding wheel 5 out of t e work and well past the dressin device, beingfinally brought to a stop 6 means, such, for example, as sclosed in theaforesaid copending application of Heald and Guild, Serial No. 629,882,filed April 4, 1923.

Referring again to Fi s. 3 and 4, a shaft 97 is rotatably carried by t ebox 93 and a lug 98 attached to; said box. An actuating arm 99 has a hub100, which latter is fastened to the shaft 97. The shaft 9'! also servesas a pivotal mounting for a second actuating arm 101. Fastened to thefront of the shaft 97 ing operation by reason o any suitableis a. lever192 The connector 62 is pivotally connected to lever 102'. The connector66 is attached to the outer end of actuating 10 1. Attached to the lefthand block 81 are a pair of switch operating dogs 103 and 104. dog 110:3is in'the pathofthe arm 99 and adapted to actuate it whenever it is:moved past said arm. The dog 105: which, as will be seen from 3, issomewhat different in shape from the dog 1 03, is in the path of theactuating arm 101, and is adapted to depress the latter whenever itpasses it. In the normal reciprocatory travel of the table to grind aworkpiece, neither the arm'lOl nor the arm 99 is actuated by the saidoperating dogs 103 and because in such working position the {table 1doeslnot move out far enough. When the table I withdraws to erform thedressi the lifting of the latch 8d as already described, the dog 103strikes and tilts the arm 99 to a position shown by dotted lines in Fig.3, as: the said table moves outwardly, and again as the said table movesinwardly, this latter time in reverse direction, but to same extent.double actuation of the arm 99 lifts the connector 62 twice, therebymoving the pawl 61 twice to operate the ratchet segment 57.

When the table 1 is in the position shown in Fig. l, which is the sitionit assumes while the operator is taking out the finished workpiece andinserting an unground one, the ratchet segment 57, pawl 61 andassociated parts, assume the full line position of Figs. 3 and i witlithe bridge 55 as shown in full lines in liig. 5. The operator havinginserted a new unground workpiece 6 in the chuck 6 of the workhead 3,grasps a lever 105 which is connected, in a manner not necessary to bedescribed herein, to the rever ing member 9. The operator shifts'saidlever- 105 to the left, thus moving the reversing member to the rightand causing the table 1 to move to the left. The table dog 8, onstriking the reversing member 9, is lifted thereover, thusdisposin themember 9 between the actuating dogs and 8. Prior to this the'dog 103strikes the arm 99, as shown in Fig. 6, and moves the bridge 55 to theposition shown in said figure, thus electrically connecting thestationary contact terminals 52 and 47. The grinding wheel 5 now roceedsto enlarge the internal diameter of t e workpiece 6, thetable'l re- 6.As the workpieceB is enlarged, at a predetermined point determined bythe adjusting screw 28, contact is made between the points 32 and 35.

Referring to Fig. 5, it will be seen that electrical energy from thegenerator G now passes along the lead 43 through the electromagnet 44,thence by way of lead 46 to terminal 47 of the switch 48, thencebybridge 5 55 to terminal 52, thence by lead 50 across the contacts 32and 35, thence through the machine frame, since the lever 24 isgrounded, back to the generator again. This causes attraction ofarmature 69, and thus the arm is raised, lifting the latch 84, whereuponthe table 1 withdraws from the workpiece for a limited distance. At thesame time, as already described, the diamond dressing point 54 islowered into the path of the grinding wheel 5 andthe latter is dressedand trued thereby. The grinding wheel 5 then returns to make contactwith the workpiece 6 again;

As. the table 1 moves outwardly for this dressing operation, the dog 103again strikes arm 99 and rocks it, bringin the bridge 55 to the positionshown in Fig. Immediately thereafter the arm 99 is rocked in the reversedirection and the bridge is-brought to the position shown in Fig. 8,where the terminals 47 and 53 are connected. At this time, as the wheel5 enters the workpiece 6 again, the terminal 32 is still in contact withthe terminal 35,.but insomuch as the bridge 55 has moved away from theterminal 52, the wheel dressing instrumentalities are not immediatelybrought into play. Instead, the grlnding wheel 5 continues to reduce theworkpiece 6, but with a greatly lessen'ed'spark, owing to the fact thatthe ressure between the two,

due to the springmg of the spindle 10, has been removed by the-dressingand truing operation, which has reduced the wheel in size. When,however, the grinding has proceeded far enough to brin the terminals 33and 36 into contact, thew eel dressing operationis repeated. At thistime, the current goes from the generator again by way of electromagnet44 and lead 46 to stationary terminal 47. Thence, it jumps by means ofthe bridge 55 to the stationary terminal 53, 'and then, by way of lead51, across the contacts 33. and 36 to ground again. This causes themachine to go through exactly'the same operation as before, and,consequently the bridge 55 is moved again. I

It will be noted that we have provided adouble motion to the bridge 55for eacham-- the machine shown. because as fully described in theapplication of Heald and Guild, Serial No.25,900 and as illustrated inFigs, 12 and 13, the said diamond 54 is returned to inoperative positionby 'a cam 1 16 carried by the table 1, a surface 117 of which engages aroller 118 Ma forward extension 119 of the lever 113, and it isdesirable that this mechanical return movement should be unopposed bypressure in the diamond operating; cylinder 112.

The wheel 5 is now back in contact with the workpiece 6 and proceeds totake the final and finishing cuts under no more pressure between wheeland workpiece than is necessary to obtain a cutting for the finish ofthe workpiece, owing to the double dressing and truing operations. Whenthe workpiece 6 reachesfinished size, the contact 34, on the lever 24,engages the stationary contact 37, and at this period, the electromagnet45 is energized] The current to energize magnet 45 proceeds, by way oflead 43, through said magnet 45 to terminal 37 by way of'lead 49, thenceto terminal 34 and back to ground. It will be noted that, at this time,it is impossible for the electromagnet 44 to be energized, since thebridge 55 has moved one station beyond the last energizing position, asshown in dotted lines, Fig. 5. Subsequent movements of the pawl 61 afterthe parts have.

reached this position avail nothing, since the pawl merely rides up onthe circular periphery of the member 57. Upon right hand movement of thetable 1, therefore, the dog 8 is lifted by the arm and, consequently,the table proceeds outwardly to the position shown in Fig. 1, where itcomes to rest. As the table so moves outwardly, and then only,

the dog 104, which is in etfecta double cam member, comes into contact.with thelever arm 101, depressing the same, thus moving downwardly theconnector 66 and raising the pawl 63. At that point thecoilspring 67comes into operation and returns the ratchet segment 57, the bridge 55,the shaft 58 and all associated parts to the original position.

This is possible because a shield member 106 holds the pawl 61 out ofengagement with the segment 57 till its stroke has been commenced.Figure 9 illustrates the action here,

showing the pawl 63 engaged by the end of the segment 57*.

It will 'be noted that the contact terminals 35 and 136, which bring thedressing instrumentalitieSinto play, are adjustable in and out, asbimeans of thumb nuts 107 and 108. Likewise, the position of finalwithdrawal" is adjustable by means of the thumb nut 109,

and as already described, the lever 24 as a unit may be adjusted in andout by means ofthe screw 28. Thus the stage in the reduction of theworkpiece at which the first and second dressing, andalso the finalwithdrawal, take place can beireadily. determined. We have nuances 7found that it is advantageous to cause the for extending the amplitudeof said reeipro- H first and second operations to come cation aplurality of times d o the operclose together and to set the diamond 54back ation on a single'work-pieee, wherehy to dress of a vertical planeof tangen y to the internal said wheel a plurality of times during saidsurfaceof the workpiece at the first predeteroperation.

position. The spring of the wheel spindle 10, whiehis combination with agrinding wheel, a work then at its maximum phase, causes the wheelholding device, and means for reciprocating 5 to contact with thediamond 54 and thus be one of said partsrelative to the other, of a dmdand trucd. As aforesaid, the wheel Wh el device having a single opernoproceeds to cut the work with greatly difl v po i i n in he Path of Saidspark, and the second dr sing wheel, and automatic means for extendingoperation'will take la e r ti ll t, that the amplitude of mid,reciprocation a plutime when the said plane of tangeney reaches filliesduring h p r i n OH the diamond, Thu a l l d i g d single workpiece,wherebytodresssaid wheel truing of the wheel is aecomplishedmiththeplurality of films during i perati ndiamond 54 always reaching the samedres c ine comprising, in coming point, yet the wheel 5 is notexcessively PP reduced, asthe spring of the spindle allows and limingtool o n d 011 d pp enough cuts to be taken between dressing op-K183115101 causing mllfive mvm crations so that the contacts 323 5 and19 and Work holder mm p 3336 will not be made simultaneously. 4 mlttmgIt is obvious that by merely providing an dude the PB d the F m theadditional pair of contacts in the box 22, an g o l e travl of andgrinder, time additional stationary terminal in the switch P g tworelative have]? 48 and some more teeth in the segment 57, we 0mm? meansor from the Shorter could provide for a triple dressing operation, a gto the longer and again a and in fact, any number of operations, but R yof limes nr ufi grinding of a beyond a certain number, such would onlyangle Workplw but P g 0f tend to excessively reduce the diameter of thethe longer g when the mg mechamsm wheel 5. As it is, with a doubledressing and has reached oth predewnnined position truing operation,bell-mouthing? of the theflfol'esald 111m 3511111195011 workpiece ispractically eliminated, and the 0f range 8 we such finish d Piece h a thi t l iumptlon after the second alteration to the onger n e. N As rebelieve ourselves to be the first to 4- A grinding machinecompnsmg,mcomprovide means for automatically a billafion, a g n 8support, a work holdmovement of the feed screw 11 resent t0 h ng r (Ptron o wheel at a plurality 'of stages in 1' a fil'llmg tool mounted onsaid support,

e course of the reduction of a workpiece, means f r lng rela ivetraverse between we wish to claim the same broadly, however the g 5ml 11 support, lncluding carried out, and 'we note in this connection11199-115 Permitting mg the W f said that while the invention isdescribed as apverse between two ranges, one of which plied inconnection with the work cali mes the parts through operative traversemechanism invented by Heald, Guild, B between the grinder and workholder alone, and Garno and described in their said appliand the other fwhich carries the parts cation Serial No. 4,466, it could equally well gg operative raverse between the be in connection with the invention of gd o he Work holder and truone of us, viz, Guild, as shown in applicationg 1, a Wot]; sizing m, means Serial No. 48,734, wherein is shown mechagt Into who wh n 1ml Work niam to automatically inaugurate the dressmecreaches a predetermined position ing and truing of the wheel in responset for altering the said traverse from the shortf f l jgtomatically wings,with means or compensa v, "causmg resum the wear on the grinding wheel.m ans preventing immediate ent re In the subjoined claims, the wordsrecipsumptlon of the longer range despite the rebate, reciprocation, andtrav r am mamtenance of sizingmechanism at said to be taken to'mean toand fro movement and predetermined pqsltio and means to againnottoinclude a movement to a position folextend the traverse to e longerrange when hired a cesation of movement. said work sizing mechanismreaches the see 2 ii 'dffifiltn dm grindingmachine,.the agrin' 'e,agrin' combination with a grinding wheel, work $1 8 Wh el devicenormally out holding means, and means for reciprocating of the path ofsaid om; of relative to the other, of a sizmgm a work means V0 tomovewheel deviee,'and automatic means ment of said sizilig mechanism forbringing said, range,

2. In an internal inc, the.

the of said traverse to insaid dressing'device into the path of saidwheel, said dressing device occupying a given point, and means forcausing said wheel to be dressed at a plurality'of different stages inthe reduction of said workpiece by relative reciprocation between "saidwheel and said dressing device, said dressing device being at such timesat said given point.

6. In a grinding machine, a grinding Wheel having a reciprocatoryworking traverse relative to the work, a truing tool, a work sizingmechanism, means set in operation by said I sizing mechanism forautomaticallyincreasing the t averse of said wheel to dress it with saidtruing tool when the work reaches a first predetermined size, meansbrought about by' said increased traverse for resuming normal.traversebetween said work and Wheel, and

means for again automatically increasing the traverse of said wheeltodress it with'said truing tool upon said work reaching asubsequentpredetermined size.

7 In a grinding machine, a grinding wheel having a reciprocatoryworkingtraverse relative to the work, means operable at a plurality ofintermediate points in the grinding o f each workpiece for amplifyingsaid traverse to carry said wheel through a wheel dressing position, agrinding wheel dresser for operating on said wheel in its passagethrough said dressing position, and automaticmeansfor avoidingthedressin g'ot' said wheel thereby on its final passage throu h thedressing position at the conclusion of t e grinding of the sameworkpiece. 7 y 8. In a grinding machine, a grinder, a

wheel dressing device normally'out' ofthe f path of said grinder, a worksizingimecha nism, and meansautomat-ically set 1n opera- 7 tion by saidsizing mechan sm for dlsposmg said dressing device in the'path of saidwheel net-ic inaugurated means for moving said diaa plurality oftimesduring theoperation on 1 a single workpiece.

2, In a grinding machine, a grinding wheel, Wheel dressmg mechanismcomprlslng a plvotally mounted diamond, and electromagmond into the pathof said wheel a plurality of times during the grinding operation on asingle workpiece. I A

10. In a grinding machine, a grinding wheel, an electrical switchmechanism adapt ed to control a primary wheel dressing operation and asecondary wheel dressing operation, a recip'rocatlng table,-'and meansactudevice out or opcrativeposition with respect;

to the grinding wheel between two or more of said dressing ope 'ations.I

12.'In a grinding machine, the combination with a grinding wheel, Workholding means, and means for reciprocating one of said parts relative tothe other, of a dressing device, and meansfor causing said dressingdevice to dress and true said grind ng wheel a plural butdeterminatenumber of, times during the grinding operation on a singlewo'rkpiece,said detcri'ninate number of dressings bein'gless in numberthan the number of reciprocations between the first and the .lastdressing operation.

13. In a grinding machine, the combination with a grinding wheel,v vorkholding means,

means for reciprocating one of said parts relative to the other, andmeans for giving said parts an intermittent cutting feed. one inrelation to the other, of a dressing device, and meansffor causing saiddressing device to dress and true said grinding wheel a plural butdeterminate number of times during a given advance of said intermittentcutting :teedgsaid determinate number of dressings beinglessin numberthan the number of separatefeed actu ations bet-weenthe first and thelastdressing operation.

14.. In a grinding machine,the combination' with; a grinding wheel, workholding means, means for reclprocatlng one of said parts relative to theother, and means for transversely feeding one of said parts relative tothe other,

of automatic means for extending the amplitude of said reciprocationaplurality of times during the operation on a single workpiece atdifferent stages of said trainsverse feed. and dressing means fordressing said wheel at said amplified reciprocations. 0 WALDO J. GUILD.LEWIS CLIFFORD KENYON ill) CERTIFICATE OF CORRECTION.

Patent No. 1,684,486. Granted September 18, 1 928, to

WALDO-J. GUILD ET AL.

It is hereby certified that error appears in the printed specificationof :the above numbered patentrequiring correction as follows: Page 2,line 111, for the word "manipulated" read "multiplied"; page 7, line 90,claim 3, after the word "travel" insert the word "and"; same claimline"94, beginning with the word 4 "but" strike out all to and includingthe word "range" in line'l00; same page,

line 110, claim 4, strike out the word "and" and insert the same beforethe word "means" line 119; same claim, line 122, strike out the commaand words "and means to again extend the traverse to the longer rangewhen said work sizing mechanism reaches the second predeterminedposition", and insert instead "but causing resumption of the longerrange when the sizing mechanism has reached another predeterminedposition, the aforesaidmeans that causes resumptionoi; the shorter rangeagain causing such resumption after the second alteration to the longerrange"; page 8, line 106, claim 14, for the misspelled word"trainsverse" read "transverse"and that the said Letters Patent shouldbe read with these corrections therein that the same may conform to therecord of the ease in the Patent Office.

Signed and sealed this 20th day of November, A. D. 1928.

p M. J. Moore, (Seal) Acting Commissioner of Patents.

